Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DA3E9C433EF for ; Tue, 21 Dec 2021 08:54:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235879AbhLUIyw (ORCPT ); Tue, 21 Dec 2021 03:54:52 -0500 Received: from mail-m973.mail.163.com ([123.126.97.3]:25832 "EHLO mail-m973.mail.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233654AbhLUIyv (ORCPT ); Tue, 21 Dec 2021 03:54:51 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=gPtm4 1ZRhN2hM6/uWkxP17bgJY7N8owgKDTDBYkkLEE=; b=HZqm69xsMl/M5Z2ptYTtS QMPPcI1giHMnW1Gm7D3H4LHkGM/D8XfdusdOH3ASlOxgVzYWGHmn4g209yyKdrhB rXT9Ayyo+h9X5UbBC1gUYxvTN9ab/w6K0KI+y3VxHptmPd0K3ZKLffQW618wcadX rINiKkHhHOsa/Wv5vxvEm4= Received: from localhost.localdomain (unknown [36.112.214.113]) by smtp3 (Coremail) with SMTP id G9xpCgB3W+8ulsFheyJVCQ--.60164S4; Tue, 21 Dec 2021 16:54:18 +0800 (CST) From: Jianglei Nie To: jejb@linux.ibm.com, jarkko@kernel.org, zohar@linux.ibm.com, dhowells@redhat.com, jmorris@namei.org, serge@hallyn.com Cc: linux-integrity@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Jianglei Nie Subject: [PATCH] security:trusted_tpm2: Fix memory leak in tpm2_key_encode() Date: Tue, 21 Dec 2021 16:54:04 +0800 Message-Id: <20211221085404.6769-1-niejianglei2021@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID: G9xpCgB3W+8ulsFheyJVCQ--.60164S4 X-Coremail-Antispam: 1Uf129KBjvJXoWxJw18Ww1kWF15GryxurykXwb_yoW5GF4DpF ZxKF1UZFWagry7Ary7JF4Svr1Ska98Gr47KwsrW39rGasxJFsxtFy7Ar4YgrnrAFWfKw15 ZF4qvFWUWrWqqwUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jhKsUUUUUU= X-Originating-IP: [36.112.214.113] X-CM-SenderInfo: xqlhyxxdqjzvrlsqjii6rwjhhfrp/xtbB3Q9wjGBHLhNxswAAs2 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Line 36 (#1) allocates a memory chunk for scratch by kmalloc(), but it is never freed through the function, which will lead to a memory leak. We should kfree() scratch before the function returns (#2, #3 and #4). 31 static int tpm2_key_encode(struct trusted_key_payload *payload, 32 struct trusted_key_options *options, 33 u8 *src, u32 len) 34 { 36 u8 *scratch = kmalloc(SCRATCH_SIZE, GFP_KERNEL); // #1: kmalloc space 50 if (!scratch) 51 return -ENOMEM; 56 if (options->blobauth_len == 0) { 60 if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) 61 return PTR_ERR(w); // #2: missing kfree 63 } 71 if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE, 72 "BUG: scratch buffer is too small")) 73 return -EINVAL; // #3: missing kfree // #4: missing kfree: scratch is never used afterwards. 82 if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed")) 83 return PTR_ERR(work1); 85 return work1 - payload->blob; 86 } Signed-off-by: Jianglei Nie --- security/keys/trusted-keys/trusted_tpm2.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c index 0165da386289..7bb1119b1dea 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -57,8 +57,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, unsigned char bool[3], *w = bool; /* tag 0 is emptyAuth */ w = asn1_encode_boolean(w, w + sizeof(bool), true); - if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) + if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) { + kfree(scratch); return PTR_ERR(w); + } work = asn1_encode_tag(work, end_work, 0, bool, w - bool); } @@ -69,8 +71,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, * trigger, so if it does there's something nefarious going on */ if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE, - "BUG: scratch buffer is too small")) + "BUG: scratch buffer is too small")) { + kfree(scratch); return -EINVAL; + } work = asn1_encode_integer(work, end_work, options->keyhandle); work = asn1_encode_octet_string(work, end_work, pub, pub_len); @@ -79,6 +83,7 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, work1 = payload->blob; work1 = asn1_encode_sequence(work1, work1 + sizeof(payload->blob), scratch, work - scratch); + kfree(scratch); if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed")) return PTR_ERR(work1); -- 2.25.1